Nitric Oxide Versus Prostaglandin E1 for Reduction of Pulmonary Hypertension in Heart Transplant Candidates

Background We sought to directly compare the effects of prostaglandin E 1 (PGE 1 ) and nitric oxide (NO) in testing for pulmonary hypertension reversibility in heart transplant candidates. Methods We included 19 heart transplant candidates who fulfilled at least 1 of 3 criteria: pulmonary vascular resistance (PVR) of >4 Wood units; transpulmonary gradient (TPG) of >12 mm Hg; or systolic pulmonary artery pressure (PAP) of >60 mm Hg. Patients randomly received either PGE 1 (0.05, 0.2 and 0.5 μg/kg/min) or NO (40, 60 and 80 ppm) and were crossed-over to the second medication after receiving the maximal dose of the first. Results With PGE 1 , TPG decreased by 21% (baseline 20.3 ± 6.8 mm Hg; final 16.0 ± 7.0 mm Hg) compared to a 34% decrease with NO (baseline 20.8 ± 6.2 mm Hg; final 13.8 ± 5.4 mm Hg) ( p = 0.13). PVR decreased by 42% with PGE 1 (baseline 6.2 ± 4.0 Wood units; final 3.6 ± 1.8 Wood units) and by 47% with NO (baseline 6.0 ± 3.9 Wood units; final 3.2 ± 1.6 Wood units) ( p = 0.87). Mean systemic pressure decreased with PGE 1 (baseline 76.1 ± 10.5 mm Hg; final 69.4 ± 12.2 mm Hg; –9%) but not with NO administration (baseline 70.2 ± 14.7 mm Hg; final 71.6 ± 10.9 mm Hg; +2%) ( p = 0.01). TPG was lowered to 1 and NO, 4 (27%) responded only to PGE 1 , and 4 (27%) responded only to NO. Conclusions The effects of PGE 1 and NO on pulmonary hypertension are comparable, with PGE 1 having more systemic hypotensive effects. Due to variability of patient responses, we recommend multiple rather than single-agent pharmacologic testing for the reversibility of pulmonary hypertension.